In conjunction with the IPCS of the WHO, a Workshop is being planned for May 1985. The Workshop is designed to accomplish three major purposes: 1) Review basic knowledge on groundwater contamination from different sources, identify capabilities and limitations of available methods for measuring groundwater quality and predicting fate of mixtures of contaminants, and recommend needed research programs; 2) Review basic knowledge on the toxic effects of individual chemicals and chemical mixtures observed in groundwater and recommend needed research programs; and 3) Provide experience and guidance to Member States confronted with groundwater contamination and rehabilitation problems by analysis of actual contamination incidents.